ISO 12571:2021 PDF

Overview

ISO 12571:2021 specifies laboratory methods to determine the hygroscopic sorption properties of porous building materials and products - key input for hygrothermal performance assessment and moisture modelling. The standard defines two alternative test routes: the desiccator method (reference method) and the climatic chamber method, both used to measure a specimen’s equilibrium moisture content at specified temperature and relative humidity conditions. Sampling is not covered by the standard.

Key Topics and Requirements

• Two test methods
  • Desiccator method (reference): uses saturated salt solutions in desiccators to establish stable relative humidities.
  • Climatic chamber method: uses a controlled chamber to set RH and temperature across the test area.
• Test conditions
  • Reference temperatures: 23 ± 0.5 °C (or 27 ± 0.5 °C for tropical climates).
  • Desiccator RH control: ±2% RH; climatic chamber: ±5% RH and ±2 K temperature uniformity.
• Apparatus & accuracy
  • Balance accuracy: ±0.01% of specimen mass.
  • Drying oven per ISO 12570 for determination of dry mass.
• Specimens
  • Minimum mass 10 g; low-density materials (